A collaborative clinical research study was described where the extent of CD4 T-cell loss caused by HIV replication was assessed in antiretroviral-naive patients. The inclusion criteria for this study were confirmed HIV infection, baseline plasma HIV-RNA, CD4 cell measurements, and at least 1 visit after 'baseline' when the CD4 cell count was measured.

The epithelial and glioneuronal cell lines derived from the female reproductive tract, brain, colon and intestine were infected using HIV clones carrying the enhanced green fluorescent protein (EGFP). Results from the infection reveal that HIV can traverse epithelial cell layers by infecting them through a gp 120-independent mechanism.